Output formats

File	For
<name>.py (always)	the parametric source: change a Dims value, rebuild everything
.step	editing in other CAD (Fusion, Onshape, FreeCAD, SolidWorks): an exact solid you can push/pull, fillet and cut, without feature history; changes there don't flow back to the script
.stl	any slicer
.3mf	slicers that read it (Bambu Studio, OrcaSlicer, PrusaSlicer); keeps units
.png	6-view preview, assembly render, section views

Bambu Studio: \"The 3mf file has invalid config, load geometry data only\"

That message is expected. The 3MF files are plain, standard 3MF (the shape, in millimeters) without a Bambu project config (printer, filament and plate settings). Click OK: the part loads normally and you slice it with your own settings. If a large part lands off the plate, use Arrange (A).

Pick them in your config (formats = ["3mf", "png"], see Settings), per run (b123d-print build --formats step,3mf), or with formats= on the MCP export tool. all means all four. Default: all four.

Files go to parts/<name>/out/. A variant's files carry its key as a suffix, and section views carry the plane and position (plate_2gang_to_1gang_xy2.45.png is the XY section at Z = 2.45).